output/recorder: dynamic file name

1 files changed, 252 insertions, 0 deletions

diff --git a/src/util/format.c b/src/util/format.c
new file mode 100644
index 000000000..d360df3dc
--- /dev/null
+++ b/src/util/format.c
@@ -0,0 +1,252 @@
+/*
+ * music player command (mpc)
+ * Copyright (C) 2003-2015 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "format.h"
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+/**
+ * Reallocate the given string and append the source string.
+ */
+gcc_malloc
+static char *
+string_append(char *dest, const char *src, size_t len)
+{
+	size_t destlen = dest != NULL
+		? strlen(dest)
+		: 0;
+
+	dest = realloc(dest, destlen + len + 1);
+	memcpy(dest + destlen, src, len);
+	dest[destlen + len] = '\0';
+
+	return dest;
+}
+
+/**
+ * Skip the format string until the current group is closed by either
+ * '&', '|' or ']' (supports nesting).
+ */
+gcc_pure
+static const char *
+skip_format(const char *p)
+{
+	unsigned stack = 0;
+
+	while (*p != '\0') {
+		if (*p == '[')
+			stack++;
+		else if (*p == '#' && p[1] != '\0')
+			/* skip escaped stuff */
+			++p;
+		else if (stack > 0) {
+			if (*p == ']')
+				--stack;
+		} else if (*p == '&' || *p == '|' || *p == ']')
+			break;
+
+		++p;
+	}
+
+	return p;
+}
+
+static char *
+format_object2(const char *format, const char **last, const void *object,
+	       const char *(*getter)(const void *object, const char *name))
+{
+	char *ret = NULL;
+	const char *p;
+	bool found = false;
+
+	for (p = format; *p != '\0';) {
+		switch (p[0]) {
+		case '|':
+			++p;
+			if (!found) {
+				/* nothing found yet: try the next
+				   section */
+				free(ret);
+				ret = NULL;
+			} else
+				/* already found a value: skip the
+				   next section */
+				p = skip_format(p);
+			break;
+
+		case '&':
+			++p;
+			if (!found)
+				/* nothing found yet, so skip this
+				   section */
+				p = skip_format(p);
+			else
+				/* we found something yet, but it will
+				   only be used if the next section
+				   also found something, so reset the
+				   flag */
+				found = false;
+			break;
+
+		case '[': {
+			char *t = format_object2(p + 1, &p, object, getter);
+			if (t != NULL) {
+				ret = string_append(ret, t, strlen(t));
+				free(t);
+				found = true;
+			}
+		}
+			break;
+
+		case ']':
+			if (last != NULL)
+				*last = p + 1;
+			if (!found) {
+				free(ret);
+				ret = NULL;
+			}
+			return ret;
+
+		case '\\': {
+			/* take care of escape sequences */
+			char ltemp;
+			switch (p[1]) {
+			case 'a':
+				ltemp = '\a';
+				break;
+
+			case 'b':
+				ltemp = '\b';
+				break;
+
+			case 't':
+				ltemp = '\t';
+				break;
+
+			case 'n':
+				ltemp = '\n';
+				break;
+
+			case 'v':
+				ltemp = '\v';
+				break;
+
+			case 'f':
+				ltemp = '\f';
+				break;
+
+			case 'r':
+				ltemp = '\r';
+				break;
+
+			case '[':
+			case ']':
+				ltemp = p[1];
+				break;
+
+			default:
+				/* unknown escape: copy the
+				   backslash */
+				ltemp = p[0];
+				--p;
+				break;
+			}
+
+			ret = string_append(ret, &ltemp, 1);
+			p += 2;
+		}
+			break;
+
+		case '%': {
+			/* find the extent of this format specifier
+			   (stop at \0, ' ', or esc) */
+			const char *end = p + 1;
+			while (*end >= 'a' && *end <= 'z')
+				++end;
+
+			const size_t length = end - p + 1;
+
+			if (*end != '%') {
+				ret = string_append(ret, p, length - 1);
+				p = end;
+				continue;
+			}
+
+			char name[32];
+			if (length > (int)sizeof(name)) {
+				ret = string_append(ret, p, length);
+				p = end + 1;
+				continue;
+			}
+
+			memcpy(name, p + 1, length - 2);
+			name[length - 2] = 0;
+
+			const char *value = getter(object, name);
+			size_t value_length;
+			if (value != NULL) {
+				if (*value != 0)
+					found = true;
+				value_length = strlen(value);
+			} else {
+				/* unknown variable: copy verbatim
+				   from format string */
+				value = p;
+				value_length = length;
+			}
+
+			ret = string_append(ret, value, value_length);
+
+			/* advance past the specifier */
+			p = end + 1;
+		}
+			break;
+
+		case '#':
+			/* let the escape character escape itself */
+			if (p[1] != '\0') {
+				ret = string_append(ret, p + 1, 1);
+				p += 2;
+				break;
+			}
+
+			/* fall through */
+
+		default:
+			/* pass-through non-escaped portions of the format string */
+			ret = string_append(ret, p, 1);
+			++p;
+		}
+	}
+
+	if (last != NULL)
+		*last = p;
+	return ret;
+}
+
+char *
+format_object(const char *format, const void *object,
+	      const char *(*getter)(const void *object, const char *name))
+{
+	return format_object2(format, NULL, object, getter);
+}